JP5299707B2 - Extrusion molding machine and method for producing porcelain plate using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extrusion molding machine and a method for manufacturing ceramic plates using the extrusion molding machine which allows the prevention of spiral orientation of clay and decrease of latent distortion when extruding the clay. <P>SOLUTION: The extrusion molding machine includes: a screw 102 for pressure-feeding the clay; a screw shaft 101 forming a shaft of the screw; an internal-ball supporting shaft 106 connected to the screw shaft; and an internal ball 107 connected to the internal ball supporting shaft. At least either the internal-ball supporting shaft 106 or the internal-ball 107 rotates reversely to the screw 102 when extruding the clay. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an extrusion molding machine for producing a large ceramic plate (ceramic plate) by molding a clay containing needle crystal minerals and then firing the clay, and a method for producing a ceramic plate using the extrusion molding machine.

  When manufacturing a large-sized porcelain plate, generally, a clay mixed with acicular mineral is extruded into a cylindrical shape by wet forming, and the dough is cut along the extrusion direction and rolled to form a substrate. In realizing this, it has been conventionally known that warpage of the fired body occurs due to kinking (helical orientation) of the clay caused by screw rotation during extrusion molding. Various improvements have been made in order to eliminate the kink of the clay that causes the warpage of the fired body, but none of them has been sufficient to eliminate the warp.

  More specifically, when making a large ceramic plate using an extrusion molding machine, generally blended dry powder of wollastonite (wollastonite), clay, and talc, which are generally acicular crystal minerals, respectively, After mixing, water is added to prepare a plastic clay, and this clay is extruded into a cylindrical shape by an extrusion molding machine, then spread into a flat plate shape, and is, for example, 4 mm thick, 1800 mm long, and wide by a rolling roller. It is finished in a ceramic plate with dimensions of 900mm.

  In this case, the extrusion molding machine includes a screw that pumps the clay, a screw shaft that forms a shaft body of the screw, a middle ball support shaft that is connected to the screw shaft, and a middle ball that is connected to the middle ball support shaft. The clay is extruded in a twisted state due to the influence of the rotation of the screw shaft.

  Therefore, a middle ball bearing case has been proposed in order to eliminate this twisting wrinkle. Since the center ball bearing case has a structure with a built-in thrust bearing, the screw shaft and the center ball support shaft are connected while maintaining an insulating state in terms of rotational force transmission. As a result, the rotational force of the screw shaft is not transmitted to the center ball support shaft by the action of the bearing, and the torsional stress is reduced. However, the spiral orientation produced by the rotation of the swirl screw has become a latent strain and tends to recover after drying and firing.

  In order to eliminate such a helical orientation caused by the rotation of the swivel screw, an extrusion molding machine described in Patent Documents 1 to 3 is known. The extrusion molding machine described in Patent Document 1 is designed to produce a large-sized plate-like sintered body having a structure in which acicular crystal minerals are oriented and aligned in the same direction. More specifically, this extrusion molding machine is a groove that twists the spiral orientation when the clay is extruded into a cylindrical shape by an extrusion molding machine and then rolled into a flat plate shape and rolled by a rolling roller. Is provided on the surface of the rolling roller.

  Further, the extrusion molding machine described in Patent Document 2 insulates the inner ball from the rotation of the inner ball shaft and fixes the inner ball to the outer body, and provides a plurality of correction plates to correct kink of the clay. Yes. More specifically, in this extrusion molding machine, the correction member provided at the rear end of the center ball is fixed to a plurality of correction plates provided radially with respect to the axis, and the rear ends of these correction plates are fixed. A cylindrical body. When the correction member is attached to the rear end of the center ball, the correction plate is radially provided on the rear surface of the center ball with respect to the axial center.

  As a result, when the clay forcibly passes between the correction plates, the spiral orientation of the clay structure caused by the rotational movement of the screw is corrected to an almost straight orientation, while facing the extrusion port. Flow on the surface of the ball.

  Further, the extrusion molding machine described in Patent Document 3 is provided with a fin that rotates the outer cylinder in the reverse direction with respect to the screw and causes the clay to flow by rotation, and also serves as a swirl flow means and an auxiliary flow means. ing. More specifically, this extrusion molding machine extrudes the clay so as to form a waveform when viewed from the extrusion direction. The extrusion molding machine is composed of a cylindrical member having a plurality of swirling fluids arranged on the inner peripheral surface of the rotating body at regular intervals along the axis thereof, and both ends are bearings and oil seals. By being externally fitted to the extrusion chamber and the nozzle through the nozzles, they are rotatably supported. Further, the swirling fluid includes a plurality of swirling blades arranged radially around the axis of the rotating body. The swirl blade is a thin plate-like member, and is fixed to the inner peripheral surface of the rotating body so that the normal direction is inclined at a predetermined angle with respect to the axial direction of the rotating body. And by having such a structure, it is trying to eliminate the rotational flaw of the clay molded body extruded from a discharge outlet.

Japanese Patent No. 2998072 Utility Model Registration No. 3145290 JP 2006-51689 A

  The extrusion molding machine described in Patent Document 1 is provided with a groove for twisting back the kink of the clay as described above in order to solve the problem of insufficient distortion reduction after the extrusion of the clay. However, since the clay has high plasticity, by providing such grooves, shear strain tends to remain. That is, in the configuration disclosed in Patent Document 1 described above, the latent strain remaining in the clay cannot be sufficiently reduced, and there is a limit in reducing the amount of warpage of the product. I couldn't say anything.

  Moreover, the extrusion molding machine described in Patent Document 2 is effective in terms of reducing kinking of the clay. However, it is conceivable that a density difference occurs in the clay in the vicinity of the correction plate due to the resistance when the clay is in contact with a plurality of correction plates. Therefore, due to the density difference of the clay, the clay does not have a uniform structure, and an uneven surface may be formed on the surface of the fired body. In some cases, the fired body itself may be deformed when the ceramic board is fired.

  Moreover, since the extrusion molding machine described in Patent Document 3 is configured to rotate the outer cylinder in a direction opposite to the screw shaft, a large shear force is applied in a direction perpendicular to the extrusion direction of the substrate. It is considered that this acts in the direction of promoting the latent strain of the clay, and the latent strain causes deformation of the fired body. For this reason, as in Patent Document 1, the latent strain remaining in the clay cannot be sufficiently reduced, and there is a limit in reducing the amount of warpage of the product. I can not say.

  An object of the present invention is to provide an extrusion molding machine that extrudes clay in a state in which the spiral orientation of the clay is suppressed and the latent strain is reduced, and a method for producing a ceramic plate using the extrusion molding machine. is there.

In order to solve the above-described problems, an extrusion molding machine according to the present invention is
An extrusion molding machine having a screw for pumping the clay, a center ball support shaft connected to the shaft of the screw, and a center ball connected to the center ball support shaft,
At least one of the middle ball support shaft and the middle ball rotates in a direction opposite to the screw during the extrusion of the clay.

  Since at least one of the center ball support shaft and the center ball provided at the rear stage of the screw rotates reversely with respect to the screw, the torsional wrinkle of the clay is eliminated, and the shear strain in the clay is offset. The deformation (warping) of the ceramic plate can be greatly suppressed.

  Moreover, the use of the extrusion molding machine according to the present embodiment makes it possible to produce a ceramic plate that is difficult to break during transportation or construction and can be used for a long time after construction.

  Preferably, the extrusion molding machine according to the present invention is provided with an insulating portion that insulates rotation in at least one of a connecting portion between the screw shaft and the inner ball support shaft, and a connecting portion between the inner ball support shaft and the inner ball. It is good to be. Insulating the rotation means that the rotation having the directivity (transmitted to the insulating portion) in the previous stage is not transmitted to the subsequent stage while maintaining the directivity, and more specifically, the rotation of the screw shaft is prevented. Shut off and make the rear middle ball support shaft or middle ball freely rotatable or displaceable according to the flow resistance of the dredged material, or use the reverse mechanism described later to support the rear middle ball This means changing the direction of rotation of the shaft or center ball.

  For example, since the rotation between the screw shaft and the middle ball support shaft can be insulated by an insulating part such as a bearing, at least one of the middle ball support shaft and the middle ball is rotated in reverse with respect to the rotation of the screw, and the other is made of clay. The flow can be freely rotated and the degree of freedom in designing the extrusion molding machine can be increased.

  Further, both the screw shaft and the center ball support shaft can be suppressed to the minimum thickness necessary for strength.

  Preferably, the extrusion molding machine according to the present invention is provided with a reversing mechanism in the insulating portion.

  Preferably, in the extrusion molding machine according to the present invention, a reversing mechanism is provided at a connecting portion between the screw shaft and the center ball support shaft, and the center ball support shaft rotates in the reverse direction to the screw shaft.

  As described above, since the reversing mechanism that reverses the rotation of the screw is provided at the connecting portion between the screw shaft and the middle ball support shaft, the middle ball support shaft rotates in the direction opposite to the screw. The twisted wrinkles of the ceramics are offset and the deformation (warp) of the ceramic plate can be greatly suppressed. Moreover, it is not necessary to perform special groove processing on the surface of the rolling roller, and a general-purpose rolling roller can be used.

  In addition, since the rotational drive source that drives the screw shaft and the center ball support shaft can be used as a single rotational drive source, the extrusion molding machine itself can be reduced in size and power consumption can be reduced.

  Further, by providing a reversing mechanism on the axis of the screw shaft and the center ball support shaft, the strain can be reduced without disturbing the orientation of the needle mineral. Moreover, it is not necessary to take other complicated embodiments such as an embodiment in which a reverse rotation drive unit is connected from the discharge port side or a counter rotating shaft, and the extrusion molding machine itself can be downsized.

  Preferably, in the extrusion molding machine according to the present invention, the center ball is insulated from the rotation of the center ball support shaft. This allows the clay to follow the flow of the clay during the process of passing through the center ball, thus effectively canceling the kink of the clay and reducing the potential distortion due to the helical orientation caused by the swivel screw. Thus, the deformation (warping) of the ceramic plate can be greatly suppressed.

  Preferably, in the extrusion molding machine according to the present invention, the rotation shaft core of the center ball support shaft is on an extension line of the rotation shaft core of the screw shaft. As a result, the twisted wrinkles of the clay can be canceled efficiently, and the potential distortion due to the spiral orientation generated through the turning of the screw can be reduced, and the deformation (warp) of the ceramic plate can be greatly suppressed. .

  Preferably, in the extrusion molding machine according to the present invention, the rotation of the center support shaft is decelerated more than the rotation of the screw shaft. As a result, the torsional wrinkles of the clay can be canceled efficiently, and the latent distortion caused by the spiral orientation caused by the turning screw can be reduced, and the deformation (warp) of the ceramic plate can be greatly suppressed.

  Preferably, in the extrusion molding machine according to the present invention, a wave gear device may be used as the reversing mechanism. By using the wave gear device as the reversing mechanism, the reversing mechanism portion can be made quite compact, and further downsizing of the extrusion molding machine itself can be achieved.

  In addition, the method for producing a ceramic plate using the extrusion molding machine according to the present invention includes a step of forming a clay into a cylindrical shape using an extrusion molding machine, a step of cutting the clay, and a step of rolling the cut clay. doing. By using the extrusion molding machine of the present invention in manufacturing such a ceramic plate, the clay is extruded into a cylindrical shape while suppressing the helical orientation, and after drying and firing, deformation (warping) that does not restore latent strain is greatly increased. It is possible to produce a ceramic plate that is suppressed to a certain level.

  According to the extrusion molding machine of the present invention, there are provided an extrusion molding machine that extrudes the clay in a state in which the spiral orientation of the clay is suppressed and the latent distortion is reduced, and a method for producing a ceramic plate using the extrusion molding machine. can do.

  In particular, when extruding the clay, by rotating either the center ball support shaft or the center ball in the direction opposite to the rotation of the screw, the shear force in the direction opposite to the screw is applied to the desired area of the clay. To compensate for the distortion in the dredged soil. As a result, it becomes possible to cancel the twisted wrinkles of the clay, and the deformation (warp) of the ceramic plate can be greatly suppressed without using a rolling roller having a special grooved surface.

  Also, by using the extrusion molding machine of the present invention, the clay is extruded into a cylindrical shape with the spiral orientation being largely suppressed, and after drying and firing, a ceramic plate that does not restore latent strain is produced. can do.

It is a longitudinal cross-sectional view which cut | disconnects and shows a part of extrusion molding machine which concerns on the 1st Embodiment of this invention along the axis line of the screw shaft or a center ball support shaft. It is a longitudinal cross-sectional view which cuts and shows a part of extrusion machine which concerns on the 2nd Embodiment of this invention along the axis line of the screw axis | shaft or a center ball support axis | shaft. It is a longitudinal cross-sectional view which cuts and shows a part of extrusion machine which concerns on the 3rd Embodiment of this invention along the axis line of the screw axis | shaft or a center ball support axis | shaft. It is a longitudinal cross-sectional view which cut | disconnects and shows a part of extrusion molding machine which concerns on the modification of the 3rd Embodiment of this invention along the axis line of the screw shaft or a center ball support shaft. It is a longitudinal cross-sectional view which cuts and shows a part of extrusion machine which concerns on the 4th Embodiment of this invention along the axis line of the screw axis | shaft or a center ball support axis | shaft. It is a disassembled slope figure which shows the inversion mechanism which makes the component of the extrusion molding machine concerning the 4th Embodiment of this invention. FIG. 6 is an exploded perspective view showing the reversing mechanism in a state where the viewing direction is reversed in the horizontal direction. It is an end elevation which shows the assembly state of the inversion mechanism with which the extrusion molding machine concerning the 4th Embodiment of this invention is equipped from the axial direction.

  Hereinafter, an extrusion molding machine according to each embodiment of the present invention and a method for manufacturing a ceramic plate using the same will be described with reference to the drawings. First, an extrusion molding machine according to a first embodiment of the present invention will be described.

  FIG. 1 is a longitudinal sectional view showing an extrusion molding machine according to a first embodiment of the present invention cut along the axis of a screw shaft or a center ball support shaft. An extrusion molding machine 100 according to the first embodiment of the present invention includes an outer cylinder 103, a screw shaft 101 disposed in the outer cylinder, and a part of the longitudinal direction of the screw shaft 101 on the upstream side in the extrusion direction of the clay. , A center ball support shaft 106 connected to the screw shaft 101, a center ball 107 connected to the center ball support shaft 106, and a reversing mechanism 110 that drives the center ball support shaft 106. have. The connecting portion between the center ball support shaft 106 and the center ball 107 is provided with an insulating portion 105 that insulates the rotation of the both, and the center ball 107 rotates in the direction opposite to the screw 102 via the reversing mechanism 110. It has become. Then, the extrusion molding machine 100 presses the clay through the screw 102 toward the center ball 107, and the clay is fed through the gap between the outer body 103 and the center ball 107 of the extrusion molding machine 100. It pushes out from the outlet side in a cylindrical shape.

  The insulating part 105 is composed of a bearing provided in the center ball, and the reversing mechanism 110 includes a universal joint 111 having one end 111a connected to the rotating shaft 120 extending from the center ball and the other end of the universal joint 111. The speed reduction mechanism 115 to which 111b is connected and the drive motor 116 connected to the speed reduction mechanism 115 are provided. The reduction mechanism 115 is composed of, for example, a gear box that accommodates a plurality of gears in mesh with each other, and the drive motor 116 is composed of a drive source capable of generating sufficient rotational torque, such as a servo motor.

  Then, the rotation of the drive motor 116 is decelerated via the speed reduction mechanism 115 and sufficient rotational torque is generated, and this rotational torque is transmitted to the rotary shaft 120 extending from the center ball via the universal joint 111. Thus, the center ball 107 rotates integrally with the rotary shaft 120 extending from the center ball. The rotation direction of the drive motor 116 corresponds to the direction in which the center ball 107 rotates in the direction opposite to the screw 102 as described above. Further, as shown in FIG. 1, the speed reduction mechanism 115 and the drive motor 116 are biased by a predetermined amount (upward in FIG. 1) from the axis of the rotating shaft 120 extending from the center ball via the universal joint 111. The speed reduction mechanism 115 and the drive motor 116 are arranged so as not to interfere with the clay extruded from the extrusion molding machine 100.

  According to the configuration of the present embodiment, since the insulating portion 105 made of a bearing is provided at the connecting portion with the middle ball support shaft 106 of the middle ball 107, the clay is pressure-fed from the screw 102 within the outer drum and is outer shell 103. In the process of being extruded from between the inner ball 107 and the middle ball 107, only the middle ball 107 rotates reversely with respect to the rotation direction of the screw shaft 101. In this process, only the center ball 107 rotates in the reverse direction with respect to the screw shaft 101, so that a reverse shearing force can be applied to the dredged soil to eliminate the dredged kink and reduce distortion. .

  Further, both the screw shaft 101 and the inner ball support shaft 106 can be suppressed to the minimum thickness necessary for strength.

  Subsequently, an extrusion molding machine according to a second embodiment of the present invention will be described. In addition, about the structure equivalent to 1st Embodiment mentioned above, the code | symbol corresponding to drawing is attached | subjected and detailed description is abbreviate | omitted. FIG. 2 is a longitudinal sectional view showing the extrusion molding machine according to the second embodiment of the present invention cut along the axis of the screw shaft or the center ball support shaft.

  The extrusion molding machine according to the second embodiment basically has the same configuration as that of the first embodiment, but differs from the first embodiment in that the screw shaft 201 and the center ball support shaft 206 are connected. An insulating part 205 that insulates the rotation of both of them is provided in the part, so that the middle ball support shaft 206 and the middle ball 207 rotate reversely with the screw shaft 201. By using the extrusion molding machine 200 having such a configuration, deformation of the fired body can be reduced when the extruded clay is spread and fired.

  In addition, as a modification of the extrusion molding machine according to the second embodiment, although not shown here, by providing an insulating portion made of a bearing or the like at the connecting portion between the center ball 207 and the center ball support shaft 206, Only the center ball support shaft 206 may be rotated reversely to the screw shaft 201 via the reversing mechanism 210. In this case, the shearing force in the reverse direction is smaller than that in the second embodiment, but it can be expected to suppress deformation of the clay after firing.

  Subsequently, an extrusion molding machine according to a third embodiment of the present invention will be described. In addition, about the structure equivalent to 1st Embodiment mentioned above, 2nd Embodiment, and its modification, the code | symbol corresponding to drawing is attached | subjected and detailed description is abbreviate | omitted.

  As shown in FIG. 3, the extrusion molding machine 300 according to the third embodiment of the present invention uses a double reversing mechanism including double reversing shafts 301 and 306 as the reversing mechanism 305. In the present embodiment, only the center ball support shaft 306 rotates in the reverse direction to the screw shaft 301. Further, in order to allow the center ball support shaft 306 to rotate in the reverse direction with respect to the screw shaft 301, an insulating portion (not shown) made of, for example, a bearing is provided at a connecting portion between the center ball support shaft 306 and the center ball 307.

  This eliminates the need to provide the universal joint, the speed reduction mechanism, and the drive motor as in the above-described embodiment on the exit side of the extrusion molding machine from which the extruded dough is extruded in a cylindrical shape. It is possible to reduce the size of the extrusion molding machine itself without being complicated.

  In addition, without providing an insulating portion between the middle ball support shaft 306 and the middle ball 307, both may be integrated and rotate in the direction opposite to the rotation direction of the screw shaft 301.

  In this third embodiment, the screw shaft 301 and the center ball support shaft 306 that constitute the counter rotating shaft 305 are provided with the same drive motor 316 and rotate in opposite directions via the planetary gear 315, for example. To slow down at the same time. As a result, the rotational drive source for driving the screw shaft and the center ball support shaft can be used as a single rotational drive source, so that the extrusion molding machine itself can be reduced in size and power consumption can be reduced.

  However, although not shown here, the screw shaft and the center ball support shaft may rotate in the opposite directions at a predetermined rotational speed via separate drive motors and reduction mechanisms.

  Subsequently, an extrusion molding machine according to a modification of the third embodiment of the present invention will be described. In addition, about the structure equivalent to 1st Embodiment, 2nd Embodiment mentioned above, its modification, and 3rd Embodiment, the code | symbol corresponding to drawing is attached | subjected and detailed description is abbreviate | omitted. FIG. 4 is a longitudinal sectional view showing an extrusion molding machine according to a modification of the third embodiment of the present invention, cut along the axis of the screw shaft or the center ball support shaft.

  In the extrusion molding machine 300 ′ according to the modification of the third embodiment of the present invention, an insulating portion is not provided between the center ball support shaft 306 and the center ball 307, and these are integrated into a screw shaft. It rotates in the direction opposite to the rotation direction of 301. And by extending the screw shaft 301 that forms the outer shaft body to the vicinity of the center ball 307 in the third embodiment described above, the periphery of the center ball support shaft 306 is covered with the screw shaft 301, and only the center ball 307 is covered. Is reversely rotated with respect to the screw shaft 301. Even if the extrusion molding machine 300 ′ having such a configuration is used, the structure on the outlet side of the extrusion molding machine does not need to be complicated as compared with the first and second embodiments described above, and the extrusion molding machine itself. Can be miniaturized.

  Subsequently, an extrusion molding machine according to a fourth embodiment of the present invention will be described. In addition, about the structure equivalent to 1st Embodiment, 2nd Embodiment, its modification, 3rd Embodiment, and its modification mentioned above, the code | symbol corresponding to drawing is attached | subjected and detailed description is abbreviate | omitted. To do.

  The extrusion molding machine according to the fourth embodiment of the present invention is the most excellent form for reducing the size and simplification of the structure of the extrusion molding machine itself among the embodiments disclosed in the present invention.

  FIG. 5 is a longitudinal sectional view showing an extrusion molding machine according to the fourth embodiment of the present invention cut along the axis of the screw shaft or the center ball support shaft. The extrusion molding machine 400 according to the fourth embodiment is characterized in that a reversing mechanism 404 is provided in the insulating portion 405a. That is, in the extrusion molding machine 400 according to the fourth embodiment, as shown in FIG. 5, a screw shaft 401 that forms the shaft body of the screw 402 is disposed at the center of the outer cylinder 403 of the extrusion molding machine. Yes.

  One end of the screw shaft 401 is supported by a thrust bearing 405 provided on one end side of the reversing mechanism 404. Further, one end of the center ball support shaft 406 is supported by a thrust bearing 405 provided on the other end side of the reversing mechanism 404. As described above, the reversing mechanism 404 is provided at the connecting portion between the screw shaft 401 and the center ball support shaft 406 and is integrally formed with the insulating portion 405 a including the thrust bearing 405.

  On the other hand, an intermediate ball 407 is supported on the other end side of the intermediate ball support shaft 406 through a thrust bearing 405 in a state insulated from the intermediate ball support shaft 406. The center ball 407 has a conical shape with a small diameter at the center ball support shaft side and a large diameter toward the side facing the base 408 of the outer body 403. A gap G for pushing out is formed.

  The thrust bearing 405 is configured as an insulating portion 405b different from the above-described insulating portion 405a. By providing the insulating portion 405b, the rotation of the center ball support shaft 406 in the previous stage is not transmitted to the center ball 407, so 407 can be freely rotated or displaced according to the flow resistance of the clay.

  The reversing mechanism 404 includes conventionally known planetary gear reducers, ball reducers, planetary roller reducers, wave gear devices ((Harmonic Drive (registered trademark)), parallel shaft gear reducers, helical reducers, worm reducers. Any of a hypoid reducer and a roller reducer can be used.

  In particular, the reversing mechanism 404 according to the fourth embodiment of the present invention includes a wave gear device, a planetary gear speed reducer, a ball speed reducer in which the rotation axis of the center ball support shaft 406 is on the extension line of the rotation axis of the screw shaft 401. Machine and planetary roller reducer are suitable. In this embodiment, a case where a wave gear device is applied will be described.

  FIG. 6 is an exploded perspective view of the wave gear device as the reversing mechanism 404. Further, FIG. 7 is an exploded perspective view of the wave gear device in a state where the viewing direction is reversed in the horizontal direction from FIG. FIG. 8 is an end view showing the assembled state of the wave gear device from its axial direction.

  6 to 8, the wave gear device as the reversing mechanism 404 includes a wave generator 409 attached to the screw shaft 401 and a flex provided at one end of the center ball support shaft 406 so as to face the wave generator 409. The spline 410 includes a circular spline 411 in which a gear 411 a that meshes with a gear 410 a formed on the outer peripheral surface of the flex spline 410 is formed on the inner peripheral surface.

  This wave gear device is a reduction gear that uses a differential between an ellipse and a perfect circle. The flex spline 410 is bent into an ellipse by a wave generator 409, and the gear 410a of the flex spline 410 is a circular spline at the long axis portion. 411 meshes with the gear 411a, and the gear 410a and the gear 411a are completely separated at the short axis portion. Accordingly, when the circular spline 411 is fixed and the wave generator 409 is rotated counterclockwise as indicated by the arrow a, the flex spline 410 is elastically deformed, and the meshing position of the gear 410a and the gear 411a is sequentially moved, so that the wave generator is moved. When 409 is rotated once, the flex spline 410 moves in the clockwise direction indicated by the arrow a ′ by the difference in the number of teeth.

  Therefore, if the wave generator 409 is attached to the screw shaft 401, the flex spline 410 is attached to the center ball support shaft 406, and the circular spline 411 is fixed to the inner surface of the outer body 403 via a support member (not shown), The rotation of the screw shaft 401 can be decelerated and the direction of rotation can be reversed and transmitted to the center ball support shaft 406.

  Hereinafter, an operation of the extrusion molding machine according to the fourth embodiment of the present invention and a method for manufacturing a ceramic plate using the same will be described. By the rotation of the screw shaft 401, the plastic clay extruded by the screw 402 is fed while turning in the outer cylinder 403 of the extruder. The center ball support shaft 406 connected to the screw shaft 401 is decelerated from the screw shaft 401 and the rotation direction thereof is reversed via a wave gear device as the reversing mechanism 404.

  With this configuration, the middle ball support shaft 406 is slowly rotated in a direction opposite to the screw shaft 401, and a stress opposite to the twist direction is applied to the clay, thereby eliminating the twisted wrinkles. Then, the clay from which the twisted wrinkles are eliminated moves toward the base 408 along the conical slope of the central ball 407 insulated from the rotation of the central ball support shaft 406, and the middle ball 407 and the base 408 are moved. Extruded into a cylindrical shape from the gap G between them (step of forming the clay into a cylindrical shape). A state in which this cylindrically extruded clay is cut open (step of cutting the clay), and the cut open clay is rolled to a predetermined size by a rolling roller (rolling step), and deformation (warping) is greatly suppressed. After drying with baked to produce a ceramic plate.

  According to the extrusion molding machine 400 according to the fourth embodiment of the present invention, unlike the conventional technique in which the screw shaft and the center ball support shaft are insulated, the center ball support shaft is always rotated. The bearing ball also rotates, and the bearing ball is worn in a uniform state to maintain the rotation of the thrust bearing. Therefore, it is considered that the durability of the thrust bearing is improved.

  Next, an example using the extrusion molding machine according to the fourth embodiment of the present invention and a comparative example using the extrusion molding machine disclosed in Patent Document 1 will be described. The conditions for comparing the two were exactly the same. Specifically, these conditions were as follows.

  Kneaded clay: After blending and mixing predetermined amounts of dry powder of wollastonite 50%, clay 40%, and talc 10%, respectively, water was added to prepare a plastic clay.

  Rolling: The dough was cut into a cylindrical shape and rolled with a roller to prepare a dough flat plate having a width of 600 mm, a length of 900 mm, and a thickness of 4 mm.

  Firing: After drying, the dough flat plate was fired in a roller hearth kiln at a maximum of 1150 ° C. to obtain a ceramic plate.

  Evaluation: About the dry flat plate before baking and the ceramic board of the fired body, the height (warpage amount) of warping at the end was measured. The measurement results are shown in Table 1.

表１における平均は、乾燥平板と焼成体の観測数（サンプル数）各１６枚に関する実施例と比較例の端部の反り上がりの高さ（ｍｍ）であり、この評価結果から実施例の方が比較例よりも端部の反り量が少ないことが分かった。また、分散は、上記実施例と比較例のそれぞれの反り量のばらつきを示す統計値であり、この値が小さいほど測定値のばらつきが小さいとされる。この分散の結果から明らかなように、乾燥平板と焼成体のそれぞれについて実施例の方が比較例よりも反り量のばらつきがかなり小さいことが分かった。

The average in Table 1 is the height (mm) of the edge of the examples and comparative examples of the number of observations (number of samples) of the dried flat plate and the fired body, and the direction of the examples from the evaluation results. However, it turned out that there is little curvature amount of an edge part than a comparative example. Further, the variance is a statistical value indicating the variation in the amount of warpage of each of the example and the comparative example. The smaller the value, the smaller the variation in the measured value. As is apparent from the results of this dispersion, it was found that the variation in the amount of warpage was considerably smaller in the example than in the comparative example for each of the dried flat plate and the fired body.

  That is, as apparent from this table, the porcelain plate formed using the example (extruder of the present invention) in both the drying state and the firing state of the prototype is the extrusion molding disclosed in Patent Document 1. It was found that the amount of warpage and its variation were less than that of ceramic plates molded using a machine. From this result, the superiority of using the extrusion molding machine of the present invention was proved.

  As described above, the extrusion molding machine according to the fourth embodiment of the present invention has a reversing mechanism for reversing the rotation of the screw at the connecting portion between the screw shaft and the middle ball support shaft, and the middle ball support shaft. Is rotated in the opposite direction to the screw shaft. By having such a configuration, the twisted wrinkles can be offset when the clay is pushed out, and deformation (warping) of the ceramic plate can be greatly suppressed.

  In order to demonstrate the operation of the present invention, as described above, as the reversing mechanism, a conventionally known planetary gear speed reducer, ball speed reducer, planetary roller speed reducer, wave gear device ((Harmonic Drive (registered trademark)) Any one of a parallel shaft gear reducer, a helical reducer, a worm reducer, a hypoid reducer, and a roller reducer can be used.

  On the other hand, as the reversing mechanism of the present invention, a planetary gear speed reducer, a ball speed reducer, a planetary roller speed reducer, and a wave gear device are used in which the rotation axis of the center ball support shaft is an extension of the rotation axis of the screw shaft. It is preferable.

  This is because by using these components, the rotation axis of the center support shaft can be on the extension line of the rotation axis of the screw shaft, so that the torsional wrinkles of the clay can be canceled efficiently. This is because the latent strain caused by the spiral orientation caused by the swirl screw can be reduced, and the deformation (warp) of the porcelain plate can be greatly suppressed.

  However, as the most preferable reversing mechanism, it is preferable to use a wave gear device (Harmonic Drive (registered trademark)). This makes it possible to minimize the shake between the axes of the screw shaft and the center ball support shaft. This is because the reversing mechanism portion can be configured to be lightweight and compact, and as a result, miniaturization of the extrusion molding machine itself can be achieved.

  In addition, since the rotation of the center support shaft is decelerated more than the rotation of the screw shaft, it is possible to effectively cancel the twisting habit of the dredged material and reduce the potential distortion due to the helical orientation caused by the swivel screw. Thus, the deformation (warping) of the ceramic plate can be greatly suppressed.

  In addition, since the center ball is insulated from the rotation of the center ball support shaft, in the process that the clay passes through the center ball, the twist of the clay can be efficiently offset, The potential distortion due to the helical orientation caused by the swirl screw can be reduced, and the deformation (warp) of the ceramic plate can be greatly suppressed.

  In addition, the method for producing a ceramic plate according to the present invention including the step of forming the clay into a cylindrical shape using an extrusion molding machine, the step of cutting the clay, and the step of rolling the cut clay is the above-described invention. By using this extrusion molding machine, the clay is extruded into a cylindrical shape while suppressing the helical orientation, and it becomes difficult to restore the latent strain after drying and firing. As a result, it is possible to manufacture a ceramic plate while greatly suppressing deformation (warping).

DESCRIPTION OF SYMBOLS 100 Extrusion molding machine 101 Screw shaft 102 Screw 103 Outer cylinder 105 Insulation part 106 Center ball support shaft 107 Center ball 110 Reversing mechanism 111 Universal joint 111a One end 111b Other end 115 Deceleration mechanism 116 Drive motor 120 Rotating shaft 200 extended from the center ball Extruder 201 Screw shaft 205 Insulating portion 206 Center ball support shaft 207 Center ball 210 Reversing mechanism 300, 300 ′ Extruder 301, 306 Counter rotating shaft 301 Screw shaft 305 Inverting mechanism 305 Counter rotating shaft 306 Center ball supporting shaft 307 Nakatama 315 Planetary gear 316 Drive motor 400 Extrusion molding machine 401 Screw shaft 402 Screw 403 Outer barrel 404 Reversing mechanism 405 Thrust bearing 405a, 405b Insulating part 406 Middle ball support 407 Nakatama 408 ferrule 409 wave generator 410 flex spline 410a gear 411 circular spline 411a Gear G gap

Claims (9)

An extrusion molding machine having a screw for pumping the clay, a center ball support shaft connected to the shaft of the screw, and a center ball connected to the center ball support shaft,
An extrusion molding machine, wherein at least one of the center ball support shaft and the center ball rotates in a direction opposite to the screw during the clay extrusion.   The insulation part which insulates rotation is provided in at least any one of the connection part of the said screw shaft and a center ball support shaft, and the connection part of a center ball support shaft and a center ball, It is characterized by the above-mentioned. Extrusion machine.   The extrusion molding machine according to claim 2, wherein a reversing mechanism is provided in the insulating portion.   2. The extrusion molding machine according to claim 1, wherein a reversing mechanism is provided at a connecting portion between the screw shaft and the center ball support shaft, and the center ball support shaft rotates in the reverse direction to the screw shaft.   The extrusion molding machine according to claim 4, wherein the center ball is insulated from rotation of the center ball support shaft.   The extrusion molding machine according to claim 1, wherein a rotation axis of the center ball support shaft is on an extension of a rotation axis of the screw shaft.   The extrusion molding machine according to claim 1, wherein the rotation of the middle ball support shaft or the middle ball is decelerated more than the rotation of the screw shaft.   The extrusion molding machine according to claim 1, wherein a wave gear device is used as the reversing mechanism. A method for producing a ceramic plate, comprising: a step of forming a clay into a cylindrical shape using an extruder, a step of cutting the clay, and a step of rolling the cut clay. A method for producing a ceramic plate, characterized in that the ceramic plate is produced using any of the extrusion molding machines.

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